
    
//A.46 StateSearchW.c 
    
   /****************************************************************** 
    
       iLBC Speech Coder ANSI-C Source Code 
    
       StateSearchW.c  
    
       Copyright (c) 2001, 
       Global IP Sound AB. 
       All rights reserved. 
    
   ******************************************************************/ 
    
   #include <math.h>  
   #include <string.h> 
    
   #include"iLBC_define.h" 
   #include"constants.h" 
   #include"filter.h" 
   #include"helpfun.h" 
    
   /*----------------------------------------------------------------* 
    *  predictive noise shaping encoding of scaled start state  
    *  (subrutine for StateSearchW)  
    *---------------------------------------------------------------*/ 
    
   void AbsQuantW( 
       float *in,          /* (i) vector to encode */ 
       float *syntDenum,   /* (i) denominator of synthesis filter */ 
       float *weightDenum, /* (i) denominator of weighting filter */ 
       int *out,           /* (o) vector of quantizer indexes */ 
       int len,        /* (i) length of vector to encode and  
                                  vector of quantizer indexes */ 
       int state_first     /* (i) position of start state in the  
                                  80 vec */ 
   ){ 
       float *syntOut, syntOutBuf[LPC_FILTERORDER+STATE_SHORT_LEN]; 
       float toQ, xq; 
       int n; 
       int index; 
    
     
       /* initialization of buffer for filtering */ 
                
       memset(syntOutBuf, 0, LPC_FILTERORDER*sizeof(float)); 
    
       /* initialization of pointer for filtering */ 
    
       syntOut = &syntOutBuf[LPC_FILTERORDER]; 
        
       /* synthesis and weighting filters on input */ 
        
       if (state_first) { 
           AllPoleFilter (in, weightDenum, SUBL, LPC_FILTERORDER); 
       } else { 
           AllPoleFilter (in, weightDenum, STATE_SHORT_LEN-SUBL,  
               LPC_FILTERORDER); 
       } 
    
       /* encoding loop */ 
    
       for(n=0;n<len;n++){ 
            
           /* time update of filter coefficients */   
            
           if ((state_first)&&(n==SUBL)){ 
               syntDenum += (LPC_FILTERORDER+1); 
               weightDenum += (LPC_FILTERORDER+1); 
    
               /* synthesis and weighting filters on input */ 
               AllPoleFilter (&in[n], weightDenum, len-n,  
                   LPC_FILTERORDER); 
    
           } else if ((state_first==0)&&(n==(STATE_SHORT_LEN-SUBL))) { 
               syntDenum += (LPC_FILTERORDER+1); 
               weightDenum += (LPC_FILTERORDER+1); 
    
               /* synthesis and weighting filters on input */ 
               AllPoleFilter (&in[n], weightDenum, len-n,  
                   LPC_FILTERORDER); 
                
           } 
            
           /* prediction of synthesized and weighted input */ 
    
           syntOut[n] = 0.0; 
           AllPoleFilter (&syntOut[n], weightDenum, 1, LPC_FILTERORDER); 
            
           /* quantization */       
    
           toQ = in[n]-syntOut[n]; 
           sort_sq(&xq, &index, toQ, state_sq3Tbl, 8); 
           out[n]=index; 
           syntOut[n] = state_sq3Tbl[out[n]]; 
    
     
           /* update of the prediction filter */ 
    
           AllPoleFilter(&syntOut[n], weightDenum, 1, LPC_FILTERORDER); 
       } 
   } 
    
   /*----------------------------------------------------------------* 
    *  encoding of start state                           
    *---------------------------------------------------------------*/ 
    
   void StateSearchW(  
       float *residual,/* (i) target residual vector */ 
       float *syntDenum,   /* (i) lpc synthesis filter */ 
       float *weightDenum, /* (i) weighting filter denuminator */ 
       int *idxForMax,     /* (o) quantizer index for maximum  
                                  amplitude */ 
       int *idxVec,    /* (o) vector of quantization indexes */ 
       int len,        /* (i) length of all vectors */ 
       int state_first     /* (i) position of start state in the  
                                  80 vec */ 
   ){   
       float dtmp, maxVal, tmpbuf[LPC_FILTERORDER+2*STATE_SHORT_LEN]; 
       float *tmp, numerator[1+LPC_FILTERORDER];  
       float foutbuf[LPC_FILTERORDER+2*STATE_SHORT_LEN], *fout; 
       int k; 
       float qmax, scal; 
        
       /* initialization of buffers and filter coefficients */ 
    
       memset(tmpbuf, 0, LPC_FILTERORDER*sizeof(float)); 
       memset(foutbuf, 0, LPC_FILTERORDER*sizeof(float)); 
       for(k=0; k<LPC_FILTERORDER; k++){ 
           numerator[k]=syntDenum[LPC_FILTERORDER-k]; 
       } 
       numerator[LPC_FILTERORDER]=syntDenum[0]; 
       tmp = &tmpbuf[LPC_FILTERORDER]; 
       fout = &foutbuf[LPC_FILTERORDER]; 
    
       /* circular convolution with the all-pass filter */ 
        
       memcpy(tmp, residual, len*sizeof(float)); 
       memset(tmp+len, 0, len*sizeof(float)); 
       ZeroPoleFilter(tmp, numerator, syntDenum, 2*len,  
           LPC_FILTERORDER, fout); 
       for(k=0;k<len;k++){ 
           fout[k] += fout[k+len]; 
       }    
            
       /* identification of the maximum amplitude value */ 
        
       maxVal = fout[0]; 
       for(k=1; k<len; k++){ 
            
     
           if(fout[k]*fout[k] > maxVal*maxVal){ 
               maxVal = fout[k]; 
           } 
       } 
       maxVal=(float)fabs(maxVal); 
            
       /* encoding of the maximum amplitude value */ 
        
       if(maxVal < 10.0){ 
           maxVal = 10.0; 
       } 
       maxVal = (float)log10(maxVal); 
       sort_sq(&dtmp, idxForMax, maxVal, state_frgqTbl, 64); 
    
       /* decoding of the maximum amplitude representation value, 
          and corresponding scaling of start state */ 
    
       maxVal=state_frgqTbl[*idxForMax]; 
       qmax = (float)pow(10.0F,maxVal); 
       scal = (float)(4.5)/qmax; 
       for(k=0;k<len;k++){ 
           fout[k] *= scal; 
       } 
    
       /* predictive noise shaping encoding of scaled start state */ 
    
       AbsQuantW(fout,syntDenum,weightDenum,idxVec, len, state_first); 
   } 
    
